Hi,

When I upgraded my BOINC, it changed my iD for the project, I tried to merge them but it didn't work.

Is there a way to revert my ID to the old one?

Thanks

Edited:
Which project? Do you mean the computer ID or your account with the project? If the computer ID, have you only upgraded BOINC or have you upgraded anything else in the computer, either hardware or Software at the same time?

LHC, I can log in fine I mean this ID:

You can't go back to the older hostID with the merge function. Merges are always oldest into newest ID's.

The only way to do what you want is to edit the client_state.xml file and change the hostID for that host across all attached projects. You also have to increment the rpc_seqno value to at least one more than the last project attempted connection count value or the client will just throw the host another new hostID.

A bit complicated but will do what you desire. You will throw away any accumulated credits by the new hostID though, so best to do this ASAP as soon as you notice the host got the new hostID.

I like this method because it preserves the host creation date for long-lived hosts at a project and the accumulated credits on the original hostID. Of course a merge will achieve the same regarding the credit totals but you lose the original creation date of the original host.

This method also doesn't confuse the 3rd party data aggregators that will show all the hostID's even of the same host multiple times if the host has been forced into a new hostID because of some change the client or project detects.

I would not mind merge but this does not work.

I don't see the last project attempted connection count value where is this?

the client_state.xml

Under Windows it's in the

C:\ProgramData\BOINC

folder (assuming you used the defaults when installing).

---

Grant
Darwin NT.

In reply to Toby Broom's message of 5 Nov 2025:

I would not mind merge but this does not work.

I don't see the last project attempted connection count value where is this?

Its in the project host Details page of any host and has mostly the same verbiage:

"Number of times client has contacted server:"

Make a note of that number on the host you want to regain the old hostID and make sure you increment that number by at least one. I always pad it by ten just to be safe. The rpc_seqno value in the client_state.xml for the old hostID gets the new padded value. You have to make note of every project that is in the client_state.xml that has had the hostID change and you want to recover and make a note of that value for each project and increment the value.

It is usually the case where only one project got the new hostID so that makes it easier. The biggest change will always be when you switch the host between OS'

That will ALWAYS change the hostID on every project and an OS change or major cpu or OS version change can never be merged so the client_state file edit is the only solution to regain the original hostID.

Thanks keith, seems to be be back lost 120 k credits vs 120 M so not too bad

+1